ACUTE SPERMATIC CORD TORSION ALTERS THE MICROCIRCULATION OF THE CONTRALATERAL TESTIS

Purpose: The purpose of this study was to characterize the hemodynamic changes in the contralateral testis during acute spermatic cord torsi on in anesthetized rats. Materials and Methods: We used videomicroscop y to examine the microcirculation of the contralateral testis followin g acute torsion. Specifically, we examined the effect on vasomotion, a rhythmic dilation and constriction of the arterioles that is involved in fluid and nutrient exchange and modulation of local vascular resis tance. In a separate set of experiments, blood flow in the contralater al internal spermatic artery was measured with an ultrasonic flow prob e during acute torsion. Results: Following 720 degrees torsion, the am plitude of vasomotion in the contralateral testis increased 121% (29.0 +/- 3.9% versus 13.0 +/- 1.7%) compared with controls. Blood flow in the contralateral internal spermatic artery decreased 43% after 2 hour s' torsion. Conclusions: Acute spermatic cord torsion altered the micr ocirculation by increasing the amplitude of vasomotion and decreased t otal blood flow to the opposite testis. Because the hydraulic resistan ce of a blood vessel exhibiting vasomotion is always less than a vesse l with the same average but static diameter, the observed microcircula tory changes may be an adaptive response to preserve local flow in the presence of decreased total flow. The long-term consequences of these changes in the microcirculation may affect testicular function and ul timately fertility.